|This article is about a/an set of monsters in Kamen Rider Ryuki.|
Once a Mirror Monster is confined through an empty Contract Card, it forms a Contract with the Rider who captured it and becomes labeled a Contract Monster (契約モンスター Keiyaku Monsutā). However, the Contract Monster can turn on their human partners and devour them if their Advent Deck is destroyed or should they decide to quit being Riders and thus starve the monster of the energy it would receive from absorbing the energies of other Monsters.
Contract Monsters do have a sense of loyalty to their human partners (examples include Darkwing, Blancwing, Destwilder, and Magnugiga). At the same time, some will get angry at their Rider when forced to do something they choose not to do (Dragreder and Gigazelle are prime examples mainly due to the attitudes of their Riders). Then, there are those who completely show utter hatred for their Rider. In Ouja's case, after acquiring Metalgelas and Evildiver, his monsters constantly attack him. However, his unstable mentality and wild personality is more than enough to tame all three of his "pets". Beforehand, Metalgelas and Evildiver had loyally served Gai and Raia, respectively, with Metalgelas even trying to avenge his master.
List of Contract Monsters
- Dragreder (ドラグレッダー Doragureddā, Japanese Dragon): Contract Monster under Ryuki, later gained enough power to evolve into Dragranzer (ドラグランザー Doraguranzā). Survived its master in the TV series.
- Darkwing (ダークウイング Dāku'uingu, Bat): Knight's Contract Monster, later gained enough power to evolve into Darkraider (ダークレイダー Dākureidā).
- Volcancer (ボルキャンサー Borukyansā, Crab): Scissors' Contract Monster, it turned on its master and devoured Scissors when his Vent Buckle was destroyed. Destroyed by Ryuki's Dragon Rider Kick with Darkwing absorbing the monster after Dragreder was told not to.
- Magnugiga (マグナギガ Magunagiga, Buffalo/Minotaur): (10-50) -A giant Ox-like robot (with a humanoid appearance similar to a minotaur) that is Kamen Rider Zolda's Contract Monster. This monster was destroyed by Ouja's Doomsday in the series.
- Evildiver (エビルダイバー Ebirudaibā, Stingray): A flying mechanical Stingray monster that was originally Kamen Rider Raia's Contract Monster. It becomes a Contract Monster under Ouja when it attempted to avenge its master in vain.
- Metalgelas (メタルゲラス Metarugerasu, Rhinoceros): An armored humanoid Rhinoceros monster that was originally Kamen Rider Gai's Contract Monster. It becomes a Contract Monster under Ouja when it attempted to avenge its master in vain.
- Venosnaker (ベノスネーカー Benosunēkā, Cobra): A giant mechanical Cobra monster that is Kamen Rider Ouja's Contract Monster.
- Destwilder (デストワイルダー Desutowairudā, Tiger): Tiger's Contract Monster. Survived its master and later destroyed by Ryuki Survive's Dragon Firestorm
- Gigazelle (ギガゼール Gigazēru, Gazelle): Originally rogue Mirror Monsters, they became Imperer's Contracts.
- Goldphoenix (ゴルドフェニックス Gorudofenikkusu, Phoenix): Odin's Contract Monster.
- Biogreeza (バイオグリーザ Baiogurīza, Chameleon): Verde's Contract Monster.
- Blancwing (ブランウイング Buran'uingu, Swan): Femme's Contract Monster.
- Dragblacker (ドラグブラッカー Doraguburakkā, Japanese Dragon): Ryuga's Contract Monster, a dark version of Dragreder. Was destroyed alongside its master.
- Psyco-Rogue (サイコローグ Saikorōgu, Cricket): Alternative Zero's Contract Monster. Survived its master upon being controlled by Yui, it was weakened by Ryuki's Dragclaw Fire to be destroyed by Knight's Hishou Zan.
- Abyssodon (アビソドン Abisodon, Shark): A mechanical shark Mirror Monster made up of Abysshammer and Abysslasher. Destroyed by Decade and Ryuki Dragreder.